Enzymes that quickly break down plastic bags have been detected in the saliva of waxworms, the larvae of moths that infect hives.
The enzymes are the first reported to break down polyethylene within hours at room temperature and could lead to cost-effective ways to recycle plastic.
The discovery came after a scientist, an amateur beekeeper, cleaned an infested hive and found that larvae had started eating holes in a plastic bag. The study showed that insect saliva may be a “repository of degrading enzymes that can revolutionize,” the researchers said [the cleanup of polluting waste]”.
Polyethylene makes up 30% of total plastic production and is used in bags and other packaging that makes up a significant portion of plastic pollution worldwide. The only large-scale recycling today uses mechanical processes and produces low-value products.
Chemical decomposition can yield valuable chemicals or, with some additional processing, new plastic, thus avoiding the need for new virgin plastic made from oil. The enzymes can be easily synthesized, the researchers said, bypassing a bottleneck in the decomposition of plastics, the initial breakdown of polymer chains. This usually requires a lot of heating, but the enzymes work at normal temperatures, in water and at neutral pH.
“My hives were infested with wax worms, so I started cleaning them, and put the worms in a plastic bag,” said Dr Federica Bertocchini, from the Center for Biological Research in Madrid. “After a while, I noticed a lot of holes and we found them It wasn’t just chewing, it was [chemical breakdown]So that was the beginning of the story.”
In terms of commercial application, the researchers say, early days are those days. “We need to do a lot of research and think about how to develop this new strategy to deal with plastic waste,” said Dr. Clemente Arias, also from the Spanish Research Centre. In addition to large recycling plants, scientists said it may one day be possible to have kits in homes to recycle plastic bags and turn them into useful products. Other scientists are currently investigating beetles and butterfly larvae for their ability to eat plastic.
Previous discoveries of beneficial enzymes were in microbes, and a 2021 study suggests that Bacteria evolve in oceans and soils around the world to eat plastic. I found 30,000 different enzymes that could break down 10 different types of plastic.
a A super enzyme that breaks down plastic beverage bottles quickly, usually made of polyethylene terephthalate plastic, was revealed in 2020, inspired by a bug found in a landfill in Japan and mistakenly modified to increase its effectiveness. The enzyme that breaks down PET was also Produced by bacteria in leaf compostwhile another Bug from landfill can eat polyurethaneIt is a widely used but rarely recycled plastic.
Millions of tons of plastic are discarded every year, and pollution is spreading across the planet, from Mount Everest summit to me deepest ocean. Reducing the amount of plastic used is vital, as is proper waste collection and treatment, and complete recycling can reduce production of new plastic.
search, Published in Nature Communications, identified 200 proteins in waxworm saliva and cut back from the two proteins that had the effect of eating plastic. This study indicates the possibility of insect saliva [be] “A reservoir of degrading enzymes that could revolutionize the field of bioprocessing,” the researchers said.
Wax worm larvae They live and grow in hives and feed on beeswax, which may be why they develop enzymes. Another possibility is that enzymes break down toxic chemicals produced by plants as a defense which are similar to some of the additives in plastic.
Professor Andy Pickford, director of the Center for Enzyme Innovation at Britain’s University of Portsmouth, said the discovery of enzymes in the waxworm’s saliva was exciting. “The reaction takes place within a few hours at room temperature indicating that enzymatic breakdown may be a pathway to benefit from waste polyethylene.”
separate study Published Tuesday in Chem . magazine He explains that creating an exact replica of an enzyme that degrades plastic means that it is more resistant to degrading itself, extending its effectiveness. But Bickford said, “The high cost of chemical synthesis of mirror-image enzymes is likely to outweigh any modest benefit from the improved enzyme half-life.”
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